Appointment of a Federal Judge to the United Nations Delegation

If this were a matter of first impression, appointing a federal judge to be a representative of the United States to the General Assembly of the United Nations would be inconsistent with the constitutional doctrines of separation of powers and independence of the judiciary. However, because of the longstanding practice of appointing federal judges to temporary office in the Executive Branch, and the absence of any explicit constitutional text, it cannot be maintained that such an appointment would be unconstitutional.